Investigating the effects of transient flow in concrete-lined pressure tunnels, and developing a new analytical formula for pressure wave velocity

2019 ◽  
Vol 91 ◽  
pp. 102992 ◽  
Author(s):  
Mehrdad Karami ◽  
Abdorreza Kabiri-Samani ◽  
Mohammad Nazari-Sharabian ◽  
Moses Karakouzian
Keyword(s):  
Wave Velocity ◽  
Pressure Wave ◽  
Transient Flow ◽  
Analytical Formula

scholarly journals Calculation Analysis of Pressure Wave Velocity in Gas and Drilling Mud Two-Phase Fluid in Annulus during Drilling Operations

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Yuanhua Lin ◽  
Xiangwei Kong ◽  
Yijie Qiu ◽  
Qiji Yuan
Keyword(s):  
Wave Velocity ◽  
Void Fraction ◽  
Pressure Wave ◽  
Angular Frequency ◽  
Mass Force ◽  
Virtual Mass ◽  
Drilling Mud ◽  
Influx Rate ◽  
Drilling Operations ◽  
Well Depth

Investigation of propagation characteristics of a pressure wave is of great significance to the solution of the transient pressure problem caused by unsteady operations during management pressure drilling operations. With consideration of the important factors such as virtual mass force, drag force, angular frequency, gas influx rate, pressure, temperature, and well depth, a united wave velocity model has been proposed based on pressure gradient equations in drilling operations, gas-liquid two-fluid model, the gas-drilling mud equations of state, and small perturbation theory. Solved by adopting the Runge-Kutta method, calculation results indicate that the wave velocity and void fraction have different values with respect to well depth. In the annulus, the drop of pressure causes an increase in void fraction along the flow direction. The void fraction increases first slightly and then sharply; correspondingly the wave velocity first gradually decreases and then slightly increases. In general, the wave velocity tends to increase with the increase in back pressure and the decrease of gas influx rate and angular frequency, significantly in low range. Taking the virtual mass force into account, the dispersion characteristic of the pressure wave weakens obviously, especially at the position close to the wellhead.

Influence of Sensitive Parameters on Pressure Wave Velocity of Gas Drilling Fluid

2021 ◽  
Author(s):  
Jiangang Shi ◽  
Wenhui Dang ◽  
Zhenxin Jiang ◽  
Hengzhi Chu ◽  
Yingjie Wang ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Pressure Wave ◽  
Drilling Fluid ◽  
Gas Drilling ◽  
Sensitive Parameters

scholarly journals Comparison of Fluid Pressure Wave between Biot Theory and Storativity Equation

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Guangquan Li ◽  
Kui Liu ◽  
Xiang Li
Keyword(s):  
Wave Velocity ◽  
Pressure Wave ◽  
Pure Water ◽  
Fluid Pressure ◽  
Pressure Profile ◽  
Pore Fluid ◽  
Biot Theory ◽  
Physical Processes ◽  
Apparent Permeability ◽  
Very High

Compressibilities of pore fluid and rock skeleton affect pressure profile and flow velocity of fluid in aquifers. Storativity equation is often used to characterize such effects. The equation suffers from a disadvantage that at infinite large frequency, the predicted velocity of fluid pressure wave is infinitely large, which is unrealistic because any physical processes need certain amounts of time. In this paper, Biot theory is employed to investigate the problem. It is shown that the key equations of Biot theory can be simplified to storativity equation, based on low-frequency assumption. Using Berea sandstone as an example, we compare phase velocity and the quality factor between Biot theory and storativity equation. The results reveal that Biot theory is more accurate in yielding a bounded wave velocity. At frequency lower than 100 kHz, Biot theory yields a wave velocity 8 percent higher than storativity equation does. Apparent permeability measured by fluid pressure wave (such as Oscillatory Hydraulic Tomography) may be 14 percent higher than real permeability measured by steady flow experiments. If skeleton is rigid, Biot theory at very high frequencies or with very high permeabilities will yield the same velocity as sound wave in pure water. The findings help us for better understanding of the physical processes of pore fluid and the limitations of storativity equation.

Limitations and pitfalls of non-invasive measurement of arterial pressure wave reflections and pulse wave velocity

2009 ◽  
Vol 3 (2) ◽  
pp. 79 ◽  
Author(s):  
Patrick Segers ◽  
Jan Kips ◽  
Bram Trachet ◽  
Abigail Swillens ◽  
Sebastian Vermeersch ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Pressure Wave ◽  
Pulse Wave ◽  
Wave Reflections ◽  
Non Invasive ◽  
Invasive Measurement

Numerical Simulation of Turbulent Pipe Flow for Water Hammer

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Hamid Shamloo ◽  
Maryam Mousavifard
Keyword(s):  
Shear Wave ◽  
Pressure Wave ◽  
Transient Flow ◽  
Water Hammer ◽  
Turbulent Pipe Flow ◽  
Turbulence Structure ◽  
Governing Equations ◽  
Structure Changes ◽  
Dominant Feature ◽  
Voigt Model

A numerical model of turbulent transient flow is used to study the dynamics of turbulence during different periods of water hammer in a polymeric pipe. The governing equations of the transient flow are solved by using the finite difference (FD) method, and the effects of viscoelasticity are modeled by means of a two-dimensional (2D) Kelvin–Voigt model. The experimental data with the Ghidaoui parameter P in the order of one are chosen in which the generated shear wave propagates toward the center of the pipe, while the pressure wave passes the length of the pipe. By studying the turbulence shear force during different times, it is shown that the turbulence structure changes considerably in the first cycle of water hammer. In the accelerated phases, the dominant feature is the creation of a shear wave near the wall, and in the decelerated phases the dominant feature is the propagation of the shear wave created in the accelerated phase.

scholarly journals Noninvasive assessment of pulmonary arterial hypertension by MR phase-mapping method

2001 ◽  
Vol 90 (6) ◽  
pp. 2197-2202 ◽  
Author(s):  
Eric Laffon ◽  
François Laurent ◽  
Virginie Bernard ◽  
Laurent De Boucaud ◽  
Dominique Ducassou ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Wave Velocity ◽  
Pressure Wave ◽  
Main Pulmonary Artery ◽  
Imaging Method ◽  
Mean Pressure ◽  
Pulmonary Arterial ◽  
The Mean ◽  
Phase Mapping

We describe a magnetic resonance (MR) imaging method that emphasizes pressure wave velocity to noninvasively assess pulmonary arterial hypertension. Both the blood flow and the corresponding vessel cross-sectional area (CSA) were measured by MR phase mapping in the main pulmonary artery (MPA) in 15 patients. MPA pressures were also measured, in the same patients, by right-side heart catheterization. Two significant relationships were established: 1) between the pressure wave velocity in the MPA and the mean pressure in the MPA (Ppa) writing pressure wave velocity = 9.25 Ppa − 202.51 ( r = 0.82) and 2) between the ratio of pressure wave velocity to the systolic blood velocity peak in the MPA (R) and the mean pressure in the MPA writing R = 0.68 Ppa − 4.33 ( r = 0.89). Using these relationships, we estimated two pressure values to frame the actual Ppa value in each patient from the present series with a reasonable reliability percentage (87%).

scholarly journals Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Norazlina Subani ◽  
Norsarahaida Amin
Keyword(s):  
Natural Gas ◽  
Pressure Wave ◽  
Transient Flow ◽  
Water Hammer ◽  
Wave Profile ◽  
Maximum Pressure ◽  
Gas Mixture ◽  
Pressure Waves ◽  
Closing Time ◽  
Closure Laws

Water hammer on transient flow of hydrogen-natural gas mixture in a horizontal pipeline is analysed to determine the relationship between pressure waves and different modes of closing and opening of valves. Four types of laws applicable to closing valve, namely, instantaneous, linear, concave, and convex laws, are considered. These closure laws describe the speed variation of the hydrogen-natural gas mixture as the valve is closing. The numerical solution is obtained using the reduced order modelling technique. The results show that changes in the pressure wave profile and amplitude depend on the type of closing laws, valve closure times, and the number of polygonal segments in the closing function. The pressure wave profile varies from square to triangular and trapezoidal shape depending on the type of closing laws, while the amplitude of pressure waves reduces as the closing time is reduced and the numbers of polygonal segments are increased. The instantaneous and convex closing laws give rise to minimum and maximum pressure, respectively.

Pressure wave propagation and input impedance in thoracic aorta of conscious newborn sheep

1995 ◽  
Vol 268 (2) ◽  
pp. H558-H568 ◽  
Author(s):  
S. L. Adamson ◽  
K. J. Whiteley ◽  
B. L. Langille
Keyword(s):  
Thoracic Aorta ◽  
Wave Velocity ◽  
Pressure Wave ◽  
Perinatal Period ◽  
Bottle Feeding ◽  
Fetal Sheep ◽  
Reflected Waves ◽  
Wave Amplification ◽  
Ventricular Afterload ◽  
Aortic Impedance

Aortic hemodynamics were examined in eight conscious newborn sheep. Flow and pressure in the thoracic aorta and pressure in the distal abdominal aorta were measured under control conditions and during pressure changes caused by bottle feeding or during intravenous infusions of nitroprusside, norepinephrine, or angiotensin II. Vasoconstriction affected aortic impedance, pressure wave amplification, and wave velocity similarly whether induced by feeding or by drugs. Central hemodynamics in the lamb were surprisingly similar to hemodynamics in the sheep fetus despite major changes in cardiovascular function at birth, largely because pressure-related increases in pulse wave velocity postpartum compensated for increased arterial lengths and increased heart rate. Wave reflection effects on pressure-flow relations were more prominent during vasoconstriction and less prominent during nitroprusside. Wave reflections in both lambs and fetal sheep return to the heart in early diastole; therefore, they do not add to ventricular afterload. Early diastolic return of reflected waves characterizes adults of many species, and demonstration of the phenomenon throughout the perinatal period reinforces arguments for its adaptive value.

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